Full-Scale Rigid Pavement Traffic Test at the FAA National Airport Pavement Test Facility – Construction Cycle 8

In May 2023, the Federal Aviation Administration (FAA) completed trafficking the final phase of Construction Cycle 8 (CC8) at the National Airport Pavement Test Facility (NAPTF). CC8 was the most complex full-scale pavement test undertaken to date at the NAPTF, and consisted of four distinct experiments: (1) a thin concrete pavement overload test; (2) a concrete-on-rigid pavement overlay test; (3) a joint comparison test; and (4) a slab strength and fatigue (S/F) test. The first three phases were completed in 2016, February 2018 and August 2018 respectively, and results from those phases are discussed elsewhere. Phase 4, the S/F test, was partially completed in 2020, but final completion was delayed due to the COVID-19 emergency. This paper presents Phase 4 test results. Unlike all previous full-scale tests at the NAPTF, CC8 Phase 4 did not involve simulated aircraft wander. Rather, all slabs were loaded on a single wheel track (zero wander) designed to isolate, and thus quantify, the number of vehicle passes needed to propagate an initial bottom-up longitudinal crack to completion. The experimental matrix considered two combinations of slab thickness and concrete strength, and 8 of the 32 slabs were constructed with a triangular notch to initiate the longitudinal crack. The initial test plan called for half the 32 slabs to be tested using a single-wheel (S), and the other half a dual-wheel (D) gear configuration. However, during testing it was found that the D configuration failed to damage the pavement, hence final traffic was changed to the higher-wheel-load S configuration for all slab groups. Ultimately, 30 of 32 slabs exhibited a full-length structural crack. The data obtained will be used to refine the bottom-up crack failure model in the FAA’s thickness design procedure, FAARFIELD. Due to the age of the concrete, the FAA will extract beams from all failed slabs for laboratory strength testing to compare with the original construction data, and may modify the analysis accordingly.